Peripheral devices for use with electronic equipment are typically equipped with small batteries in order to provide a device package that is compact in size and light in weight. By way of illustration and not limitation, examples of peripheral devices may include Bluetooth headsets, smart watches, keypads, computer mice, pointers, and other types of devices. These peripheral devices are sometimes referred to as accessory devices, and the two terms are used interchangeably herein. The power consumption of peripheral devices may be significant relative to the battery capacity. There is a need for techniques to drive down power consumption on such devices without compromising user experience.
Security and control of access to smartphones and other electronic devices is very important, but access control is currently an area of poor user experience. For example, password-based authentication schemes have been used in smartphones for a long time. However, passwords are unwieldy for smartphones and result in a suboptimal user experience. Over the past few years, smartphones have included several alternative types of user authentication such as facial recognition and fingerprint recognition. Such biometric authentication systems often have a high likelihood of failure. For example, facial recognition systems are very sensitive to lighting conditions, whereas fingerprint sensors are quite sensitive to the cleanliness of the fingertip and the sensor. Other access control mechanisms include keeping the smartphone unlocked when attached to a Bluetooth peer or a specific Wi-Fi access point; however, such mechanisms have inherent security loopholes.
Passwords and security codes used to authenticate users are prone to security problems, particularly when such passwords are simple. Users prefer to set up simple passwords or personal identification numbers (PINs) to make them easier to remember, and to make it faster to unlock the smartphone. At the same time, simple passwords may be easier for onlookers to watch and read.
Electronic access control mechanisms are not limited to the smartphone environment. Of perhaps even greater significance are electronic mechanisms for controlling access to physical locations such as buildings, homes, or cars. Conventionally, electronic badges are used to allow access to offices. Badges generally are equipped with a radio frequency identification (RFID) tag, which is scanned by an RFID reader at a point of entry or access point to allow access to the holder of the badge. If the badge is lost, there is a significant security problem—a person who finds the badge may be able to access the office. It is easy to see that a similar problem exists with conventional car keys, home keys, and office keys.
RFID technology uses electromagnetic fields to transfer data. RFID tags are attached to objects and are “read” by RFID readers. These RFID tags may be powered solely by RF power received from the RFID reader, or by magnetic induction, or the RFID tags may be equipped with a battery. In addition to access control, another exemplary use of RFID technology is to track objects and manage inventory. RFID is preferable over barcodes for many applications since the tag does not need to be in a line of sight of the reader.
An operation of reading an RFID tag can be used as a trigger to perform some other action or actions. One such illustrative system is described in U.S. Pat. No. 8,862,052, entitled “NFC mobile communication device and NFC reader.” Likewise, a method of using RFID to initiate a connection between a handheld device and a base unit is described in U.S. Pat. No. 7,236,742, entitled “System and method for wireless data transfer for a mobile unit”, Univ. Brigham Young.